Spreader assemblies of the prior art such as shown for example in U.S. Pat. Nos. 3,248,117 and 3,282,591 include stationery hoppers of a funnel shape for receiving the grain to be distributed within a storage bin. The distributor or scattering assembly receives the grain from the lower end of the hopper for scattering about the bin. A motor in or on the hopper rotates the scattering assembly at various speeds with such assembly being axially tiltable relative to its vertical axis of rotation in response to the rotational speed thereof. The tilt position and rotational speed of the scattering assembly determines the pattern of grain distribution.
In the spreader of U.S. Pat. No. 3,248,117, the scattering assembly at the discharge portion thereof is provided with adjustable vanes to further vary the distributing pattern. Since these spreaders are dependent upon centrifugal action for scattering the grain, the larger particles of grain are distributed peripherally of the bin while smaller particles along with fines and like refuse material are distributed centrally of the bin. Uniformity of material dispersion is thus impaired even though uniformity in the level of grain in the bin may be satisfactory. This disparity of grain density transversely of the bin appreciably shortens the period during which the grain can be stored without spoilage.